"The Drumhead" was the 21st episode in the 4th season and written by Jeri Taylor. It was directed by Jonathan Frakes (Commander Riker) and starred screen legend Jean Simmons as Ret. Admiral Norah Satie.
The story begins with the questioning of a Klingon science exchange officer who is being accused of sabatoge of a dilithium chamber in engineering. He is found guilty of exchanging secret information with federation enemy Romulus, but the engineering team, lead by Geordi and Data, proves that the explosion was an accident by faulty parts used in a routine maintenance.
During the trial of the Klingon, a medic, who had given medical injections to him, was questioned about how well he knew the exchange officer. He only knew him in sick bay and in Ten Forward, but in a social gathering. However, the admiral's Betazoid assistant senses he's hiding something crucial and an investigation begins into his personal life.
The medic, named Tarses, is now undergoing a public hearing and he, on advice of acting council William Riker, refuses to answer questions about his Romulan heritage. This encourages the admiral to continue investigating the entire crew, to weed out conspirators with the go-ahead of Starfleet command.
Lt. Worf is all too eager to assist her in this effort and Captain Picard has a one-on-one talk with him about the dangers of suspicion turning into paranoia. He tells Worf this reminds him of a "drumhead" used on the battlefield where officers would gather and dispense quick judgments and severe punishments without an appeal.
Picard then tries to stop any further interrogations of the crew by telling the admiral he will do whatever he can to fight her on it. She responds by putting him on the witness stand at another public hearing with an admiral from Starfleet security in attendance. She grills him on the Romulan spy who passed herself off as a Vulcan ambassador and questions whether or not he is fully recovered from his incident with The Borg.
As part of his defence and as an objection to the hearings, Picard quotes the admiral's own father, a man she idolizes, by saying ""With the first link, the chain is forged. The first speech censured, the first thought forbidden, the first freedom denied, chains us all irrevocably." With this, the admiral loses it and yells "I've brought down bigger men than you, Picard!" and rails about him dirtying the name of her father.
The Security admiral from Starfleet leaves the proceedings and later calls a halt to them completely.
I like this episode because it is well acted and gives us thought about today's political climate regarding "the war on terror" and our reaction to acts of violence such as illegal searches, wiretapping, and the censorship of important public information by the government.